Engine cam operated air compressor for vehicle leveling system

ABSTRACT

IN PREFERRED FORM, A COMPRESSOR HAVING AN OPEN ENDED HOUSING ADAPTED TO BE CONNECTED TO A CAM PORT ON AN ENGINE BLOCK. AN OPERATING ARM IS DRIVEN BY AN ENGINE CAM TO RECIPROCATE A PISTON WITHIN AN OIL FILLED CYLINDER WHICH INCLUDES AN INTAKE VALVE TO A SUMP IN THE HOUSING AND A RELIEF VALVE FOR FLOW OF EXCESSIVE OIL FROM THE CYLINDER BACK TO THE PUMP. A PUMP DIAPHRAGM IS OPERATED BY RECIPROCATION OF THE PISTON IN THE CYLINDER TO DRAW AIR INTO AND DISCHARGE AIR FROM AN AIR PUMPING CHAMBER WHICH INCLUDES A PLURALITY OF SHALLOW, NORROW RELIEF PASSAGEWAYS THEREIN TO REDUCE RE-EXPANSION OF COMPRESSED AIR IN THE CHAMBER. AN IMPROVED OIL BAFFLING ARRANGEMENT PREVENTS AERATION ON THE OIL SIDE OF THE DIAPHRAGM.

June 20, 1972 5, w, JACKSON ETAL 3,671,150

ENGINE CAM OPERATED AIR COMPRESSOR FOR VEHICLE LEVELING SYSTEM Flied Sept. 21, 1970 2 Sheets-Sheet 1 6601" e jwnfi James dzmrd Whe/an ATTADKIFV June 20, 1972 G. w. JACKSON m 3,67

ENGINE CAM OPERATED AIR COMPRESSOR FOR VEHICLE LEVELING SYSTEM 2 Sheets-Sheet 2 Filed Sept. 21, 1970 @zorge James C'daum Whelan Zwuw/ ATTORNEY United States Patent ice US. or. 411-395 Claims ABSTRACT OF THE DISCLOSURE In preferred form, a compressor having an open ended housing adapted to be connected to a cam port on an engine block. An operating arm is driven by ,an engine cam to reciprocate a piston Within an oil filled cylinder which includes an intake valve to a sump. in the housing and a relief valve for flow of excessive oil from the cylinder back to the sump. -A pumpdiaphragm is operated by reciprocation of the piston in the cylinder to draw air into and discharge air from an air pumping chamber which includes a plurality of shallow, narrow relief passageways therein to reduce re-expansion of compressed air in the chamber. An improved oil bafiiing arrangement prevents aeration on the oil side of the diaphragm.

This invention relates to air oil compressors and more particularly to compressor devices having an oil pump on one side of a diaphragm for operating the diaphragm to pump air into and out of an air pumping chamber.

One reliable type of air compressor includes a pumping diaphragm which is operated to pulse within an air pumping chamber to draw air into the chamber and discharge it therefrom at a higher pressure.

Such pumps include an oil filled cylinder on one side of the diaphragm in which is located a piston that reciprocates in the cylinder to displace the diaphragm into and out of the air chamber to compress air.

, In cases where the piston is operated by an engine cam it will reciprocate at high speeds. To get good air pumping action the diaphragm must smoothly sweep the chamber at a high rate of reciprocation.

This can cause problems including loss of oil from the system which can cause the oil filled cylinder to be partly drained, thereby to effect the smooth pumping action of the diaphragm.

Another problem can be that of aeration of the oil during the operation of the device. Aeration is caused in part by oil flow back to a sump region of the pump. When the pump oil is aerated it no longer will act as a solid column on the diaphragm and its smooth pumping action at high rates of reciprocation may become erratic.

Still another problem is that of re-expansion of compressed air in the air compressing chamber of such devices following the discharge stroke.

- Under circumstances where the oil piston is reciprocated at high speeds it is necessary to provide for a pumping cavity configuration which allows for unrestrained high speed movement of the diaphragm in the air pumping chamber. Additionally, the rapidly moving diaphragm must be smoothly moved into and out of air passages in 3,671,150 Patented June 20, 1972 an engine cam and including an oil filled sump region 'for continuously supplying oil to an oil filled cylinder having a piston therein with a displacement in excess of that of the air displacement of a pump 'diaphr'agmwhich closes one end of the cylinder and wherein oil return flow lfrom the oil filled cylinder to the sump region passes through an oil return chamber having a bafiie for preventing aeration of oil in the sump during compressor operation.

Still another object of the present invention is to improve air-oil compressors having a pump diaphragm for compressing air in an air'chamber wherein'the air chamher is formed in part by a head member which is configured to cooperate with a central portion of the diaphragm and a reverse bend hinge section thereon-to minimize re-expansion of compressed air following" the discharge stroke of the diaphragm and-to permit smooth reciprocation of the pump diaphragm throughoutits suction and discharge pump strokes within the air chamber. These and other objects of the present invention are attained in one working embodiment which includes a pump housing having an open end adapted to be connected around an engine cam port in an'engine block. The housingincludes a lower oil sump for supplying oil to an oil filled cylinder formed by a tubular extension that is arranged concentrically within a semi-circular upper surface on the housing that overlies the sump region. The semi-circular upper surface is closed at one end by a depending batlle to form an oil return passageway which communicates with an oil outlet port from the cylinder which is directly in line with the baflie whereby oil returned from the cylinder to the sump flows evenly through a narrow passageway without causing aeration of oil within the sump. A flexible pump diaphragm has an undeformed outer peripheral segment thereon held in sealing engagement against the housing by a cylinder head which has an air pumping chamber therein. The diaphragm includes an undeformed central portion and a reverse bend hinge portion thereon joined to the outer peripheral segment of the diaphragm. The air pumping chamber in the headincludes a radially outwardly located bevelled annular surface thereon adapted to supportingly receive the hinge segment of the diaphragm. It further includes a centrally located flat surface thereon which is intersected at spaced apart points thereon by relief grooves each of which includes radially outwardly directed segments thereon formed along a radius line from the center of the cavity. The radially outwardly directed segments are joined together by grooves that are on chord lines of a circle at the outer periphery of the fiat. surface of the head. A larger diameter groove extends along the surface on the diameter of the circle and is in perpendicular intersecting relationship with the previously mentioned chordal grooves. The larger groove is intersectedat one end thereof by a small diameter opening leading to a discharge air valve and at the opposite end thereof by a small annular opening in the fiat surface of the cavity which surrounds the head of an intake air valve. This configuration enables the diaphragm to be rapidly reciprocated to and fro within the air pumping cavity without restraint and further enables it to discharge all of the intake air from the cavity during a discharge stroke with a minimum of reexpansion. of compressed air following the discharge stroke. I Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

. FIG. 1 is a view in vertical section of an air-oil compressor having a movable pump diaphragm therein driven by a piston reciprocated in an oil filled cylinder;

- 'FIG. 2 is an end elevationalview taken along the line 2-2 of FIG. I looking in the direction of the arrows;

FIG. 3 is a vertical sectional view taken along the line 33 of FIG. 1 looking in the direction of the arrows; FIG. 4 is a cross-sectional view taken along the line 4'4 of FIG. 3 looking in the direction of the arrows; FIG. 5 is a vertical sectional view taken along the line 55 of FIG. 1 looking in the direction of the arrows; FIG. 6 is an enlarged sectional view taken along the line 6-6 of FIG. 3 looking in the direction of the arrows; F IG. 7 isan enlarged sectional view taken along the line 7-7 of FIG. 3 looking in the direction of the arrows; FIG. 8 is a vertical sectional view taken along the line 8--8 of FIG. 1 looking in the direction of the arrows;

FIG. 9 is a vertical sectional view taken along the line 99 of FIG. 4 looking in the direction of the arrows; and

'FIG. 10 is a vertical sectional view taken along the line 1010 of FIG. 1 looking in the direction of the arrows.

. Referring now to FIG. 1, a compressor 10 is illustrated including a. housing 12' which is connected to an engine block 14 around a cam port '16 therein by means of screws 17.

The cam port 16 leads to a crankcase which has a cam shaft 18 therein with a lobed cam element 20 which is in engagement with an. elongated end 22 of an operating arm 24 which has the opposite end 26 thereof located within the interior 28 of the housing 12 at a generally right angular disposition with respect to the crankshaft located end 22.

The operating arm 24 is supported by a shaft 30' having the opposite ends thereof secured to opposite walls of the housing 12. Upon rotation of the shaft 18 the cam 20 will operate the arm 24 to pivot about the axis of the shaft 30 thereby to cause the end 26 to oscillate within the interior 2-8 of the housing 12.

The housing 12 supportingly receives the radially outwardly located flanged end 32 of a cylinder assembly 34 at a groove 36 in the open end thereof. An annular O-ring 38 is seated between the flanged end 32 and the groove 36 to seal one face thereof and a second O-ring 40 is seated in the flanged end 32 to sealingly engage the outer peripheral edge of a perforated stop plate 42 which in cludes a raised central portion 44 thereon having'a plu rality of small diameter openings 46 throughout the planar extent thereof as best seen in FIG. 8..

The cylinder assembly 34 more particularly includes an elongated tubular extension 48 which supportingly receives the grooved sidewall 50 of an open end piston 52 that has a closed end 54 thereon in engagement with a round-tip 56 on the inwardly located end 26 of the operating arm 24.

The piston 52 receives one end of a return spring 58 which has the opposite end thereof supported by the perforated back stop plate 42 thereby to urge the piston 52 outwardly of the tubular extension 48 and the cylinder assembly 34.

The cylinder assembly 34 is filled by oil which is maintained at an oil level 60 within the interior 28 of the housing 12.

Oil level 60 is formed above a lower sump 62 in the housing 12 which is formed in part by an inclined base 64 on the housing 12 which leads downwardly to an oil intake valve assembly 66 to the interior of the cylinder assembly 34. The intake valve assembly 66 more particularly includes a spherical head 68 with a stem 70 which receives one end of a spring 72 having the opposite end thereof seated in a groove in the flanged end 32. The spherical head 68 seats against an annular spherical seat 74 in the flanged end 32.

When the return spring 58 moves the piston 52 outwardly of the tubular extension 48 the volume of the space 75 between the piston 52 and the cylinder assembly 34 is increased. To maintain the cylinder assembly.34

filled with oil the intake valve assembly 66 will open thereby to allow flow of oil from the sump region 62 into the volume 75 as it increases.

In accordance with certain principles of the present invention the oil intake action of the valve assembly 66 is dependent upon the operation of an air pump diaphragm 76 which includes an undeformed outer peripheral segment 78 thereon joining to a central segment 80 by an annular reverse bend hinge section 82.

The diaphragm is a flexible synthetic plastic material which is supportingly received by the perforated back plate 44 as the piston 54 is moved out of the oil filled cylinder assembly 34.

The diaphragm 76 cooperates with a cylinder head 84 to form an air pumping chamber 86 into which air is drawn during a suction stroke and discharged during a compression or discharge stroke.

More particularly the head 84 is secured to housing 12 by a plurality of screw elements 88 which extend through the diaphragm 76 and the perforated stop plate 42 into threaded engagement with an end 90 on the housing 12. Thus, the undeformed peripheral part of the diaphragm 76 is held in sealing engagement between the outer periphery of the perforated stop plate 66 and the head 84.

A cavity 92 in the head '84 includes an annular bevelled surface 94 thereon which merges with a flat central surface 96 which is spaced from and in coaxial alignment with the bent central segment 44 of the perforated stop plate.

The bevelled surface 94, flat surface 96 and the diaphragm 76 together define the total volume of the compression or pumping chamber 86.

Air is supplied into the pumping chamber through an intake valve assembly 98 which includes a flanged cup 100 that is seated against an annular gasket 102 within a large diameter opening 104 in the head 84.

The opening 104 is formed by an upstanding flange 106 which is crimped at circumferentially spaced points 108 thereon to secure the flange portion of the cup 100 to the head 84 and define an opening 110 in communication with an intake tube 112 on the flanged cup 100 and an intake bore 114 in the head through which is located the stem 116 of an intake valve 118. The base of the intake valve is in engagement with one end of a flat coil spring 120 that has the opposite end thereof in engagement with the head 84 to bias a flat head portion 122 of the intake valve 118 into sealing engagement with an annular gasket 124 which is seated in an opening 126 which intersects the flat surface 96 of the cavity 92.

The head 122 has its end surface 128 in the same plane as that of the surface 96 and as a result only a narrow annular opening 130, best seen in FIG. 3, is present at the intake valve assembly 98. This is the only cavity opened and below the surface of the central portion 96 of the cavity 92 at the valve assembly 98.

In accordance with certain principles of the present invention, air passing through the intake valve assembly 98; when the valve initially opens, flows into the" annular opening 130 and thenin back of the diaphragm through a shallow relief groove in the surface 96 which extends from the annular opening 130 to a small diameter dis charge opening 134 at the opposite end thereof.

The small diameter discharge opening 134 is closed by a valving element 136 maintained in a sealed-seated rethe outer edge of the head 84 as is best seen in FIG. 2.

In accordance with certain principles of the present invention, the discharge pressure of air from the cavity 86 is maintained at/or below a predetermined value established by a relief valve assembly 152 which is formed as an integral part of the cylinder assembly 34.

More particularly, the relief valve assembly 152 includes a sheet metal cage 154 which is fixedly secured at one end thereof to the flange 32 around an outlet or discharge bore 156 therein.

The cage 154 is formed by a plurality of spaced apart straps and has an end opening 158 therein which allows free flow of oil from the discharge opening or bore 156 into a return oil passageway 160.

The valve assembly 152 more particularly includes a valving element 162 maintained against the flange 32 around the bore 156 therein by means of a relief spring 164.

During the operation of the device, the displacement of the piston 52 is greater than that of the diaphragm 76 and as a result following a predetermined discharge stroke the piston 52 will overtravel a slight degree to assure that the diaphragm 76 will fit tightly against the head 84 to completely discharge air from the cavity 92 therein.

At this point, the further travel of the piston 52 into the tubular extension 48 will produce a pressure increase therein which will cause the valve 162 to open and discharge a high pressure jet of oil through the bore 156.

One problem is that this high pressure jet of oil can cause aeration of the oil in the sump 62 and a consequent frothing of the oil. When this occurs the piston 52 is no longer able to force a solid column of hydraulic fluid against the oil side of the diaphragm 76 and as a result the pumping efficiency of the compressor is reduced.

To prevent this problem, in accordance with certain other principles of the present invention, the housing 12 and the tubular extension 48 together form a labyrinth path for flow of oil from the bore 156 back to the sump 62. More particularly, and as best seen in FIGS. 5 and 7, the return passageway 160 is blocked at one end thereof by a depending bafile member 166 formed integrally with the housing 12 to join a pair of curved surfaces 168, 170 thereon which are formed in a semi-circular manner above the sump region 62 and in close spaced relationship to the upper surface of the tubular extension 48.

Between the surfaces 170, 168 is defined a narrow oil flow passageway 172 and a narrow oil flow passageway 174 that flows downwardly across the upper surface of the extension 48 into the sump region 62 from the return passageway 166.

The oil return passageway 160 serves to diffuse a high pressure oil jet from the bore 156 to prevent entrainment of air into the oil and to cause the kinetic energy of the jet to dissipate so that return oil will flow in a smooth laminar stream through the narrow passageways 172, 174 directly back into the sump region without agitation of the surface of oil level 60 for return flow through the inlet valve assembly 66. The return flow occurs on the suction stroke of the piston 52 wherein the return spring 58 forces the piston 52 outwardly of the tubular extension 48. 1

In accordance with certain other principles of the present invention in addition to providing a smooth return oil flow back to the sump region 62 the relief valve assembly 152 constitutes a built-in upper pressure limit for an associated pneumatic system. An oil fill port 175 in body 12 is blocked by plug 177 as seen in FIG. 5.

Another feature of the present invention is that the head 84 in addition to including the groove 132 includes a plurality of transverse relief grooves therein which serve as a means to assure free movement of the diaphragm between its suction position wherein it engages perforated stop plate 42 and its discharge position wherein it is supported by the bevelled surface 94 and the fiat surface 96 of head 84.

More particularly the grooves include radially directed slots 176 which are formed across the bevelled surface 94 and into the flat outer surface of the head 84 on the underside of the undeformed portion of the diaphragm.

Each of the slots is located on a radius through the center of the surface 96.

A pair of the slots 176 on the bevelled surface 94 in the direction of the small diameter discharge opening 134 are joined by a shallow relief groove 178 which is directed across the chord line of a circle which forms the outer periphery of the surface 96.

A second pair of the slots 176 which are adjacent the annular opening to the intake valve assembly 98 are joined by a groove 180 which is along a chord line which intersects the annular groove 130.

Another one of the slots 176 is formed across the bevelled surface 94 to intersect the annular opening 130 and be in line with the groove 132 and yet another of the slots 176 is formed across the bevelled surface 94 to intersect the discharge opening 134.

These slots and grooves together form a relief path for fluid flow between the diaphragm and head. This enables the diaphragm to be quickly moved from its discharge to suction positions without being sucked against the head 84 during the suction stroke in a manner that can effect the rapid diaphragm reciprocation produced by high speed operation of the operating arm 24 driven by engine cam 20.

The grooves are of a size which can be manufactured but are large enough to reject air from the cavity on high speed reciprocation. They have a width which is narrow enough to prevent the diaphragm from closing off flowinto either the discharge opening 134 or from the annular opening 130 when the diaphragm is in engagement with the head 84.

However, the diaphragm at the end of the discharge stroke does completely fill the shallow grooves and slots 176, 178,180 thereby to completely sweep discharged air into the small diameter discharge bore 34 and the annular opening 132 whereby re-expression of compressed air is limited to these two small volumes formed in the head 84.

Another feature of the invention is the construction of operating arm 24. It includes side walls 182, 184 joined by a bight portion 186 to define a scoop 188 facing in the direction ofcam port 16. Oscillating of the arm tends to move oil out of sump 62 and force it outwardly of the housing 12. To prevent oil loss, the present invention includes a 20 mesh wire screen 190 between walls 182, 1 84.

It is connected at its upper end to shaft 30 and extendsacross the full width and height of scoop 180 to prevent pump-out of oil from sump 62. The solid oil column between arm 24 and the housing 12 will flow upwardly in the arm and will then splash out toward the screen 190. The screen is sized to permit free fiow of the solid column of oil into the arm. It prevents oil from splashing outwardly of the arm through the'cam port 16 into the crankcase.

In one working embodiment of the invention the compressor 54 has a displacement of .2 cubic inch per stroke.

Therelief valve assembly 152 is set at a blow-off pressure form through p.s.i.g.

When the compressor is connected in an automatic leveling system of the type having a combination shock absorber and air spring unit with a control chamber having a mean height volume of 70 cubic inches the compressor is able to level the vehicle when the engine cam 20 is operated at idle speed to compensate for a 1200 pound load including 900 pounds of passenger and 300 pounds of trunk load within 5 to 7 minutes. The compressor when driven by the engine cam operating at a highway speed of 70 mph. is able to pump-up and level the load within 3 minutes.

In order to accommodate the high speed operation of the diaphragm, the compressor in one working embodiment included the following characteristics:

Component: Rating Pump diaphragm surface 80 Pump diaphragm material 1.20 inches diameter. Groove 132:

'D 22011 Du Pont Spec. W 0.30to .035 inch. 1 R .010 inch.

R .015 to .020 inch. Grove 178:

D .025 to .020 inch. W .020 to .015 inch. R .010 inch. R .010 to .015 inch.

The compressor operates as follows:

As shown in FIG. 1, the compressor is at the end of a suction stroke wherein the diaphragm 76 is supported across its full planar extent by the perforated stop plate 44.

At this point in the cycle the lobe of the cam is moved in a clockwise direction to press against the end of the arm 22 thereby to cause the operating arm 24 to pivot about the shaft 30 and cause the rounded tip 56 on the end 26 to press against the piston 52 to cause it to move inwardly of the tubular extension 48 against the spring 58.

This reduces the volume of the chamber 75 and oil forced from the chamber 75 moves through the perforations 46 in the back-up plate 44 against the oil side of the pump diaphragm 76 to move it into the air filled chamber 86. During this discharge stroke the inlet valve 98 remains closed and air from the air pumping chamber 86 is forced through the small diameter opening 134 across the valving element 136 through the discharge fitting 146.

Further inward movement of the piston 52 produces a further reduction of the volume of the chamber 75 and the excessive oil continues to move against the oil side of the diaphragm 76 till the diaphragm 76 is pressed against the bevelled surface 94 and the central flat surface 96 of the cavity 92 and also is flattened into the grooves 76, 78, 132, thereby to completely discharge air from the chamber 86 through the discharge opening 134.

The oil displacement by the piston 52 from the tubular extension 48 is is an excess of the air volume displaced by the diaphragm 76 when it moves from its supported position on the perforated back-up plate 44 to its position against the head 84. As a result, the diaphragm is firmly pressed into the grooves 176, 178, 180 and 132 and thereby only the volume of the annular passageway 130 and that of the small diameter discharge opening 134 remains following the discharge stroke. As a result, there is very little re-expansion of compressed air upon the return movement of the diaphragm 76 on a suction stroke. The piston 54 continues to move inwardly of extension 48 to a point where the pressure in the variable volume chamber 75 reaches the blow-off pressure of the relief valve 152. This occurs when the diaphragm is against the head 84 following the discharge stroke or when the air system is at a pressure in excess of the relief pressure of valve 152. The relieved fluid passes from the valve 152 and is directed by the bafiie 156 and the semi-circular surfaces 170, 168 back into the sump 62 without causing the oil in the compressor 10 to be aerated or to froth.

The next phase of operation is a suction stroke which occurs following the relief action of the valve 152. At this point the cam element 20* is moved away from the end 22 of the operating arm 24 so as to allow the end 2 6 to move in a clockwise direction about the axis of pin 30 thereby to allow the return spring 58 to move the piston 54 outwardly of the tubular extension 48. At the very beginning of the suction stroke, the pressure differential required to open the oil inlet valve 66 is greater than that required to open the air intake valve assembly 98. As a result, air first enters the chamber 86 on the air side of the diaphragm 76 across the valving element 116 which has atmospheric or a pressure in excess of atmospheric acting thereon across a differential area which overcomes the spring force of spring 120. The air thus begins to flow into the network of grooves 132, 178, etc. completely across the air side of the diaphragm to assure that it will freely move from the head 84 during the suction stroke. After the diaphragm has bottomed out on stop plate 44 the oil intake valve 66 opens to fill the increasing volume of the cavity 75 with oil from the sump 62. The inlet oil flow continues until the piston 52 has been moved into its most extended position with respect to the tubular extension 48 as illustrated in FIG. 1.

By virtue of this structure, the diaphragm may be reciprocated at a high rate, as for example, that rate of movement which is produced by a revolving cam element on a camshaft of an automobile engine. Hence the compressor 10 is capable of high volume output and because of its anti-frothing characteristics and the additional means for assuring a low level of air rte-expansion following a discharge or compression stroke the compressor is able to operate at an unusually high volumetric efficiency which assures that it is a reliable source for high pressure within a pneumatic system such as, an automatic leveling system of a vehicle; a high pressure air braking system or the like.

While the embodiments of the present invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is:

1. An air oil compressor comprising: a housing, means defining an oil sump in said housing, a cylinder within said housing, a piston supported within said cylinder for reciprocation therein, means for causing said piston to reciprocate into and out of said cylinder, a perforated stop plate covering one end of said cylinder, a spring biasing said piston outwardly of said cylinder, said cylinder including an inlet valve therein in communication with said oil sump, a relief valve in said cylinder controlling flow of oil from said cylinder back to said sump, a diaphragm overlying said stop plate, a cylinder head, a cavity in said cylinder head formed in part by a flat surface, an air intake valve into said cavity including a valving element having a head portion thereon in the same plane as that of said flat surface, means defining a small annular opening between said air intake valve and said head, said intake valve being movable into a chamber between said cavity and said diaphragm as said diaphragm moves into supported relationship with said perforated back stop member, an air discharge valve from said cavity including a small diameter opening in communication with said flat surface of said cavity, an air discharge valving element, spring means for biasing said air discharge valving element to close said discharge opening to control discharge flow from said chamber, and means including a plurality of shallow grooves in said cavity for permitting unrestricted movement of said diaphragm into overlying relationship with said flat surface thereof to discharge air completely from said cavity each time that said piston is moved interiorly of said cylinder.

2. A compressor to be driven by an engine cam comprising: a housing having an open end adapted to be connected to the engine block at a cam port therein, means defining an oil sump in said housing in communication with the engine crankcase through the cam port, a cylinder within said housing filled with oil, a piston supported within said cylinder for reciprocation therein, an operator arm having one end thereof directed outwardly of said open end of said housing and having the opposite end thereof in engagement with said piston, means for pivotally connecting said operator arm to said housing for pivotal movement thereon to cause said piston to reciprocate into and out of said cylinder, a perforated stop-plate covering one end of said cylinder, a spring biasing said piston outwardly of said cylinder, said cylinder. including an inletvalve. therein in communication with said oil sump, a relief valve in said cylinder controlling flow of oil from said cylinder back to said sump, a diaphragm overlying said stop plate, said diaphragm including an undeformed peripheral portion thereon and a movable central portion thereon connected to said peripheral portion by an annular reverse bend segment thereon, a cylinder head, means for sealingly connecting said undeformed peripheral portion of said diaphragm between said cylinderhead and said housing, a cavity in said cylinder head including an annular bevelled portion thereon adapted to supportingly receive the reverse bend segment of said-diaphragm and a flat central surface portion thereon adapted to supportingly received the central portion of said diaphragm, an intake valve into said cavity including a-valving element having a head portionthereoninthe same plane as that of said central portion, meansdefining a small annular opening between said valve and said head, said intake valve being movable into -a chamber between said cavity and said diaphragm as said diaphragm moves into supported relationship with said perforated back stop member, a discharge valve from said cavity including a small diameter opening in comrnunication with said central surface of saidcavity, a valving element, spring means for biasing said valving element to close said discharge opening to control air flow from said chamber, and means including a plurality of. shallow grooves in said cavity for permitting unrestricted movement of said diaphragm into overlying relationship with said bevelled portion of said cavity and saidflat central surface thereof to discharge air completely from said cavity each timethat said piston is moved interiorly of said cylinder by said operating arm.

3. An engine cam driven compressor comprising: a housing having an opened end adapted to be connected to an engine blockat a camv port therein, means defining a bottom sump in said housing in communication with the engine crankcase through said openend of said housing, a semi-circular surface at the top.of said housing, a bafiieplate on said housing cooperating with said semi-circular surface to form an oil return relief space, a cylinder having a tubular extension aligned concentrically of said semi-circular surface and defining therewith a restricted oil flow path to said sump, a piston within said tubular extension defining therewith a variable volume oil chamber, a perforated stop plate at one end of said oil chamber, a flexible pump diaphragm overlying said perforated plate closing said oil chamber, said cylinder having an inlet ,valve therein communicating said sump with said variable volume oil chamber, a relief valve in said head for flow of oil therefrom into said oil return space when a predetermined pressure occurs within said variable volume chamber, a cylinder head connected to said housing, a cavity formed in said head having a bevelled peripheral portion thereon and a flat central surface thereon,v said diaphragm being movable upon reciprocation of said piston interiorly of said tubular extension to engage said bevelled portion 'and said flat surface, an air intake valve in said head including a valving element having a head portion thereon with a flat planar surface located in the plane of said central surface of said cavity, spring means for maintaining said valving element closed, a discharge valve in said head including a small diameter opening intersecting said fiat surface at one side thereof, a valving element in said opening, discharge spring means biasing said valving element closed, said air discharge valve opening at a point prior to flow of oil through said relief valve back to said oil sump, means to permit free unrestrained movement of said diaphragm completely against said bevelled surface and said fiat central surface, said means including a pair of grooves in said head including radially outwardly directed segments thereon formed radially with respect to the center of said central surface portion of said cavity and a chordal'segment thereon intersecting the radial portions, a diametric groove in said surface intersecting said annular groove around said inlet valve and intersecting said small'diameter bore, said radial segments, 'said chordal segments and said diametric groove cooperating to form a path for flow of high pressure air completely from said cavity into either said small diameter opening or the annular opening around said valve for limiting the re-expansion of compressed fluid in saidcavity when said diaphragm is moved by intake air flow through said intake valve in a direction against said perforated support plate.

4. In an air oil compressor the improvement comprising: a housing having an open end thereon adapted to be connected to a cam port on an engine block, an operating-arm having one end thereon extending through said open end and the opposite end thereof located within said housing, means for pivotally supporting said arm on said housing, an oil sump in said housing, said housing including a semi-circular surface overlying said sump, a baflie' plate on said housing cooperating with said semicircular surface to form an oil return passageway, an oil pumping cylinder within said housing, a tubular extension arranged generally concentrically of said semicircular surface having an upper surface located immediately below said semi-circular surface in close spaced relationship therewith to define a narrow curved return opening between said extension and surface for oil flow from said oil return passageway back to said sump, said extension having an underside above said sump, said bafile having a curved bottom edge located closer to said extension than said semi-circular curved surface to block one end of the passageway to cause oil return to flow through said narrow curved return opening thence to the underside of said extension to said sump, a piston within said cylinder supported for reciprocation within said tubular extension by pivotal movement of said operating arm, means for spring biasing said piston outwardly of said cylinder, means for closing said cylinder at one end thereof including a perforated back stop plate and movable diaphragm, an air cylinder head secured to said housing for sealing said diaphragm at the periphery thereof to said housing, means forming a cavity in said head for receiving said diaphragm and defining therewith an air pumping chamber, inlet valve means into said chamber, exhaust valve means from said chamber, said piston reciprocating within said cylinder to force oil against one side of said diaphragm for forcing it into said cavity to exhaust air therefrom, said piston being returned by said spring to cause said diaphragm to be moved by atmospheric pressure acting thereagainst to move into engagement with said perforated back stop plate and produce an intake of air into said cavity during a suction stroke of said diaphragm, said cylinder including an oil intake valve between said housing sump and said cylinder operative to open as the piston moves exteriorly of said cylinder to draw oil into said oil cylinder only after said inlet air valve opens to assure free unrestrained movement of said diaphragm into engagement with said backstop, and a relief valve in said cylinder operative to relieve oil from said cylinder including an outlet opening in said oil return passageway from which oil is diverted by said bafiie into said curved return opening when a predetermined air discharge pressure acts on said diaphragm, said oil flow through said narrow opening being a smooth laminar oil flow into said sump to prevent aeration of oil Within said sump reglon.

5. In an air oil compressor the improvement comprising: a housing having an open end thereon adapted to be connected to a cam port on an engine block, an operating arm having one end thereon extending through said open end and the opposite end thereof located within said housing, means for pivotally supporting said arm on said housing, said inwardly located end of said arm having a pair of .spaced apart side walls joinedtogether by a bight portion thereon, said spaced apart arms and said bight portion forming a scoop facing in the direction of said open end of said housing, an oil sump in said housing, said inwardly located end extending into said oil sump and tending to move oil from said sump through said open end into the crankcase of they engine, said housing including a semi-circular surface overlying said sump, a bafile plate on said housing cooperating with said semi-circular surface to form an oil return passageway, an oil pumping cylinder within 'said housing including a tubular extension arranged generally concentrically of said semi-circular surface in close spaced relationship therewith to define a narrow curved return for oil from said oil return passageway back to said sump, a piston within said cylinder supported for reciprocationwithin said tubular extension by pivotal movement of said operating arm, means for spring biasing said piston outwardly of said cylinder, means for closing said cylinder at one end thereof including a perforated back stop plate and a movable diaphragm, an air cylinder head secured to said housing for sealing said diaphragm at the periphery thereof to said housing, means forming a cavity in said head for receiving said diaphragm and defining therewith an air pumping chamber, inlet valve means into said chamber, exhaust valve means from said chamber, said piston reciprocating within said cylinder to force oil against one side of said diaphragm for forcing it into said cavity to exhaust air therefrom, said piston being returned by said spring to cause said diaphragm to be moved by atmospheric pressure acting thereagainst to move into engagement with a perforated back stop plate and produce an intake of air into said cavity during a suction stroke of said diaphragm, said cylinder including an oil intake valve between said housing sump and said cylinder operative to open as the piston moves exteriorly of said cylinder to draw oil into said oil chamber only after said inlet air valve opens to assure free unrestrained movement of said diaphragm into engagement with said back stop, a relief valve in said cylinder, operative to relieve oil from said cylinder into said oil return passageway when a predetermined air discharge pressure acts on said diaphragm, said oil returning back to said sump through said narrow opening as a smooth oil flow to prevent aeration of oil within said sump region, a screen .element supported in said inwardly located end of said operating arm between the two side walls thereof operative to permit flow of oil droplets into a space between the two side walls of said inwardly located end for return flow therefrom back into said sump region without being scooped by said inwardly located end through the open end of said housing into the engine crankcase. 1 v v 6. -A compact high-capacity cam operated compressor comprising: a housing having an open end thereon, an operating arm having one end thereof extending outwardly of said open end and an end located within said housing, means for pivotally supporting said'operating 1 2 arm on said housing forcausing oscillation of said inwardly located end of said housing, a housingsump, ta semi-circular surface on said housing overlying said sump, a depending ba-flle on said housing extending between side portionsof said semi-cirmular surface, a cylinder, ,a tubularextension on said cylinder extending, generally concentrically of said :semiecircular surface having an upper surface located immediately below said semi-circular surface in .close spaced relationship therewith to define a narrow curvedop ening between said extension and surface, said extension havingan underside above said sump, said bafile having a curved bottom edge located closer to said extension than said semi-circular-surface to block one end of the passageway to cause oil return to flow through said narrow curved return opening thence to the underside of said extension to said sump, a relief valve in said cylinder for returning oilfrom within said cylinder back to said sump region, said relief valve having aport therein in alignment withrsaid depending bafile whereby relieved oil is directedagainst said depending baflle to pass as a laminar flow through the narrow space between said semi-circular surface; portions of said housing and said tubular extension backxinto said sump without agitating or aerating the oil therein, a piston within said tubular extension, spring means for biasing said piston outside ofsaid tubular extension, an oilsintakervalve in said cylinder, said operating arm reciprocating said piston within said cylinder against the biasing action of said spring to cause oil to be drawn into'the cylinder from the sump region through said oil intake valve, a diaphragm closing an open end of said cylinder and being reciprocated by movement of oil into and outof said cylinder during reciprocation of the piston therein, means including a cylinder head and said diaphragm defining an air pumping chamber, an air intake valve to said chamber and an air outlet valve therefrom, said air intake valve to said pumping chamber being conditioned to open before flow of oil from the sump region across the oil intake valve insaid cylinder during .a suction stroke on the air side of'said diaphragm, said piston having a displacement in excess of that of said diaphragm as it moves in a discharge direction so that following discharge of air from the compressor the piston continues to move in the direction of said diaphragm to cause excess oil to be directed by said relief valve back into said narrow oil return passageway for controlled return flow into said sump to eliminateaeration of the oil durin reciprocation of said piston with said cylinder;

References Cited UNITED-STATES PATENTS 3,153,381 10/1964 Holley, Jr. 417,-3ssx 1,840,527 /1932v Rabez zara 417-395 X 3,496,875 2/1910 Van Allen et a1, 417-495 ROBERT M. WALKER, Primary" Examiner j $99233? UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 316711150 Dated June 1972 lnvencorg's) G. W. Jackson and James E. Whelan It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

C o1umn 1, line 68, "charatceristics" should be characteristics Column 6, line 40, "re-expression" should be re-expansion Column 6, line 64, "form" should be from Column 7, line 5, after "80" insert in the "Rating" column 1.20 inches diameter Column 7, line 6, delete "1.20 inches diameter" and insert 22011 Du Pont Spec. Column 7, line 8, delete "22011 Du Pont Spec." and insert ---O.3O to .035 inches Column 9, line 16, "received" should be receive and Column 12, line 5, "cirmular" should be circular Signed and sealed this 20th day of February 1973..

(SEAL) Attest:

ROBERT GOTTSCHALK Commissioner of Patents EDWARD I IQFLETCHER,JR. .-\ttesting Officer 

